Mushrooms in Houseplants: Why They Appear (And Are They Poisonous?)

It can be a bit of a shock when mushrooms turn up in your houseplants. Due to their lifecycle, they can literally turn up overnight.

If you’re thinking ‘is my plant going to be ok? A mushroom’s turned up literally overnight and I’m panicking’, rest assured:

• Your plant is more than likely totally fine
• The mushroom won’t harm your plant
• It’s not dangerous to touch, but don’t eat it. They’re classified as medium toxic, so even one will give you a bad stomach upset
• If kids or pets eat one, get them medical attention (though they’re unlikely to cause lasting harm)
• At best, your soil is very nutritious
• At worst, your soil is staying too damp and you need to either lay off the watering or help it drain better

If that’s answered all your questions, go about your day.

If you’re just super confused about how your houseplant went and found itself a little friend seemingly out of nowhere, read on.

What is the mushroom in my houseplant?

A houseplant mushroom isn’t just any mushroom.

By which I mean that it’s a specific species. I kind of made that sound like it was a magic mushroom. Or a mushroom with superpowers. Which it definitely isn’t.

Chances are the mushroom that just appeared in your potted plant is Leucocoprinus birnbaumii, also known as the plantpot dapperling.

It could be another species of Leucocoprinus, such as Leucocoprinus cepistipes, but an absolute identification doesn’t really matter. It’ll probably be a Leucocoprinus of some description.

They can grow either singly or in a clump (I’ve had both in my plants). The cap can get up to 7.5cm across, but the ones that turn up in houseplant soil tend to be quite small, tall and thin, because there’s only so much water and nutrients to go around and they have to compete with your plant.

They probs look something like this:

They may not, and that’s okay. Feel free to DM me a picture on Instagram and we’ll see if we can identify it. Be quick though, because they often don’t last more than a couple of days.

Yellow, white, green or brown: does the colour matter?

Leucocoprinus birnbaumii is usually lemon yellow, but it can vary in colour depending on where it is in its lifecycle and the nutrients in your soil. Houseplant mushrooms can be white, green or brown too.

• Yellow: almost certainly Leucocoprinus birnbaumii
• White: often a L. birnbaumii that has faded with age
• Pale green: still most likely a Leucocoprinus
• White or cream with a brown dot in the middle: probably Leucocoprinus cepistipes, which is bigger, wider and flatter than L. birnbaumii

Whatever the colour, the advice is the same. Don’t eat it, and don’t panic about it.

Other names for Leucocoprinus birnbaumii

Due to the long and varied history of trying to classify Leucocoprinus birnbaumii, they can be given a variety of names:

• Plantpot dapperling
• Yellow parasol
• Flowerpot parasol
• Yellow houseplant mushroom (fair enough)
• Lemon yellow lepiota
• Yellow pleated parasol
• Lepiota lutea

Where did the mushroom in my houseplant come from?

Leucocoprinus birnbaumii used to live exclusively in the tropics and the subtropics. They weren’t found in northern Europe because it’s too cold.

Hilariously, they were first described (i.e. formally identified as a newly encountered species) in 1788 in Halifax by the English mycologist James Bolton. Yeah, where Last Tango in Halifax was set. A good few thousand miles from where they’re supposed to be.

He called it Agaricus luteus because he hadn’t expected to find a tropical mushroom growing in a hothouse in Halifax, so assumed it was a species that grew closer to home. It was named in 1839 after a garden inspector called Birnbaum found it in a greenhouse. And then it turned up in London. And Prague. All of these are distinctly non-tropical places.

Due to this tendency to hitchhike around the world, Leucocoprinus birnbaumii wasn’t correctly classified until 1962, when Rolf Singer reclassified Leucocoprinus luteus as Leucocoprinus birnbaumii.

At this point you might be thinking, ‘why does the species of mushroom matter? I want to know why it grew in my plant.’

The species does matter because Leucocoprinus birnbaumii is very, very good at spreading via potting soil.

It travelled from the tropics to Europe in our houseplants. It turned up a lot in greenhouses and hothouses but likely wasn’t an issue for the general public until central heating became commonplace.

In short, houseplant mushrooms are a direct result of the houseplant industry. They came over in imported plants, their mycelium likely attached to the roots of the tropical plants destined for the trade, and occasionally pop up, freaking out everyone.

There are now Leucocoprinus birnbaumii living wild in the forests of England. It was like they planned it all along.

Houseplant soil from the growers

The most likely explanation is that the spores were there all the time, and have been since your plant was first potted up and grown on in a commercial nursery.

Mushrooms produce billions of spores, which they eject out of their gills. The spores are then carried by the wind (or, in our case, by us) and spread that way.

The reason this particular species frequently turns up in houseplant soil is that the potting mix suits it. It’s a tropical fungus, and the potting mix is designed for a tropical plant.

The spores are so tiny my brain can’t really comprehend them, but a single button mushroom can produce billions of spores. So one tiny mushroom in a commercial greenhouse could easily get spores into every pot. And we can probably imagine there’s more than one, because a greenhouse is the perfect place for Leucocoprinus birnbaumii to grow and reproduce.

Growers could eradicate them, but houseplant mushrooms are saprotrophic, which means they feed on decaying matter in the soil and won’t harm the plants.

This is also why they can crop up at any time, even years after you bought the plant. The mycelium can lie dormant in the soil for years until the conditions are right.

Mushrooms in bags of potting soil

Bagged potting soil can also come with added mushrooms, but I would treat this as a good thing. The presence of fungi suggests that the soil hasn’t been treated with fungicides or pesticides, and a dark, warm bag of soil is the perfect place for them.

They can be a sign that the soil is nutrient-rich. This, like the mushrooms themselves, is not an automatic indicator of ‘good’ soil. Nutrients are a component of good soil, but they’re not the whole picture.

They could have come in on you

If you’re near a mushroom that’s releasing spores in a garden centre (I honestly have no idea how likely that is) they could get caught on your clothes, and then fall into a houseplant.

These things can travel from Malaysia to Prague, I’m sure a trip from your sleeve to the soil is nothing to it.

Just think: if your cat was near a mushroom releasing its spores, got some on its fur, and then went for a kip in your Monstera, it wouldn’t take much for a spore to set up shop in the soil.

Why has a mushroom suddenly appeared in my plant?

Short answer: the conditions were right.

If it seems like your houseplant mushroom was gone one minute and fully formed the next, it’s because they spend a long time forming and then appear one day, looking like they’ve been there for weeks.

And then, a couple of days later, there’s no sign that they’ve been there at all.

The mushroom is the fruit of the fungus. It popped up, spread its spores, shrivelled up, and then more or less reabsorbed itself.

The real power behind the mushroom is the mycelium, which is a network of fungal threads called hyphae that act like a root system, absorbing water and nutrients. The lifecycle of Leucocoprinus birnbaumii is basically: fall into pot, germinate, grow mycelium, eat a load of decaying matter, produce a mushroom, release spores, reabsorb mushroom, repeat.

If you tip your plant out of its pot, you might spot fine white threads running through the soil. That’s the mycelium, and it’s the bit that sticks around after the mushroom has gone.

And you might be thinking ‘…wait, if my houseplant’s pet mushroom just released a few million spores around my house, why aren’t there mushrooms popping up in all my plants?’

Good question. It’s because the spores need the right conditions to germinate, and the mycelium needs the right conditions to fruit. Most of those spores land somewhere that just isn’t warm, damp and nutritious enough.

What conditions do houseplant mushrooms need?

I’ll briefly run through them, but remember that mushrooms can just turn up. Whilst they’re more likely to turn up in certain conditions, these are guidelines, not rules. A bit like how spider mites love dry, bright places, but will turn up on a Calathea in December.

Light

The natural habitat of Leucocoprinus birnbaumii is the forest floor, usually in leaf litter, or perhaps near a rotten tree. It’s usually pretty shady around there, but there might be dappled light.

Mushrooms are more likely to turn up in shaded areas, but they can grow in bright light. Plants in bright light can shade the soil, so whilst the plant is in bright light, the mushroom isn’t.

Humidity

Leucocoprinus birnbaumii will likely only produce mushrooms in a humid environment, so if your home has very dry air, you might never see one. The spores need humidity to germinate, so they’re less likely to grow in cacti, but they could germinate in a peace lily.

Once the spore has germinated, the mycelium will start to grow, but the mushrooms won’t grow unless the right conditions are met. That could be next week, or in 10 years.

My Monstera dubia produced a mushroom when I put it in the bathroom and then had a shower. It’s never produced another since I moved it into the bedroom.

Temperature

Spores need quite warm temperatures to germinate, so the fruit won’t develop until it’s warm enough, otherwise it’s a waste of a couple of billion spores. This is why they’re most common in July and August when it’s hot and humid and we’re feeding our plants more.

So if your home rarely gets warm and humid, you won’t get many mushrooms in your houseplants. Again, I’ve had them pop up in my chilly bathroom, so they sometimes manage to find a way.

Water

Mushrooms like growing in damp soil. They are highly unlikely to grow if the soil isn’t wet. The soil could be moist enough deep down for the spore to germinate, but if the top few inches regularly dry out, you’ll likely never get mushrooms appearing.

Pothos get them quite often, because they’re often kept in low light, so the soil doesn’t dry out very quickly and stays moist for longer. Dark + moisture = mushrooms.

Mushrooms are also less likely to turn up in terracotta pots, but since a lot of overwaterers offset their habits by using terracotta pots, don’t take this as gospel.

Nutrients

They can’t produce a fruit if they don’t have the nutrients. The nutrients in your houseplant pot will depend on, er, what’s in the substrate. Some people use compost, which would be good for Leucocoprinus birnbaumii, but even better for fungus gnats, which is why I don’t use it.

Some garden centres (particularly the chains) pot houseplants up in outdoor potting soil (i.e. a tonne of compost), with stuff added to make it airier. I find my houseplants grow perfectly well in it, but it’s more likely to yield mushrooms (and fungus gnats).

Are houseplant mushrooms poisonous?

Yes and no. Leucocoprinus birnbaumii are toxic to eat, but not to touch.

They’ve not had their ‘official’ toxicity measured, but they’re classified as ‘medium poisonous’. This means that if you eat a lot you’ll get a very bad stomachache and feel very ill, but there are unlikely to be any long-term effects unless you’re allergic to them. You’d probably need to eat about a dozen to do real damage, but let’s be safe rather than sorry.

In short, don’t eat them.

There are very few fungi that are poisonous to touch, so as long as you wash your hands well afterwards, feel free to pluck mushrooms from your plant pots without gloves.

Leucocoprinus cepistipes is thought to be less toxic, but it’s not tasty either. Let’s all just agree not to eat mushrooms that weren’t bought from a knowledgeable vendor or forager, ok?

What if my pet or child eats one?

They won’t harm your plant, but they might harm your pets or kids, so if you have any of those hanging around, it’s best to get rid of the mushrooms.

Don’t worry unduly. A cat or dog would need to eat a LOT of Leucocoprinus birnbaumii to do any real damage, but it may still result in a trip to the vet, so better safe than sorry.

Can I still eat herbs that have mushrooms growing in the pot?

As far as I’m aware, as long as your herbs weren’t touching the mushrooms they should be perfectly safe to eat. Best wash them extra thoroughly just in case though.

Are mushrooms in houseplants bad?

No, mushrooms in houseplants are typically benign, and don’t mean that there’s anything wrong with your plant.

However, they need certain conditions to grow (heat, moisture, nutrients), which can cause some houseplants issues. For example, a mushroom growing in a Calathea pot is likely fine, because they have broadly the same care requirements. A mushroom growing in a jade plant could be a sign that the pot and soil are staying wet for too long.

They won’t harm your plant

Whilst there are species of parasitic fungi out there, Leucocoprinus birnbaumii aren’t one of them. In the wild, they live in the leaf litter of tropical rainforests eating up all the decaying matter.

They won’t damage the roots and they won’t cause any hideous diseases. The mycelium will just chill in the soil, eating nutrients until the conditions are right and it pops up a mushroom.

They do eat nutrients

This isn’t really a negative or a positive. It has the potential to be both, I suppose.

On the plus side, they’ll break down decaying matter, like dropped leaves. The downside is that they’re also potentially taking nutrients away from your plants. If you fertilise your plants regularly then this won’t be an issue, but if it’s been a few years since you either repotted or fed your plants, the mycelium is potentially taking nutrients your plant needs.

Are mushrooms a sign of overwatering?

They can be, because Leucocoprinus birnbaumii need damp soil and high humidity.

When you see a mushroom in your houseplant pot, don’t assume you’ve overwatered, but do take the time to check the roots and the soil, just in case.

In general, I wouldn’t worry about mushrooms in plants that also come from damp places in the tropics, like rainforests. So Calathea, ferns, peace lilies, Aglaonema, some Philodendron, bird of paradise, spider plants, Monstera, some Anthurium… there’s probably more.

However, there are some plants that shouldn’t really be in soil staying damp enough to grow a mushroom. Plants like snake plants, succulents, cacti, aloe and jade plants should be in a very well-draining mix that’s unlikely to provide a good home for a houseplant mushroom.

If your snake plant does have a mushroom, it’s not necessarily got root rot, but check just in case. It could have a layer of compost or some other nutrient-rich humus on top that gave the mushroom decent conditions, whilst the substrate below is free-draining.

They can also turn up on big succulents, because when leaves drop (from old age or whatever) they slowly release stored moisture into the soil.

I’d be very surprised if a mushroom turned up in a Hoya or a Phalaenopsis, but it really depends on the substrate and where you keep them. I keep mine in very chunky potting mixes that have very little nutrition (they’re epiphytes, so I soak them in nutrient water every so often).

Should you find a mushroom in one of those plants, check the roots and consider either putting it in a better potting mix or moving it to a warmer, brighter spot so the soil can dry out more quickly. In my experience, it’s usually a light/warmth issue rather than a soil issue.

Your soil might lack airflow

Mushrooms need oxygen just as much as roots, but they need less than many plants. A lot of climbing aroids, for example, prefer very well-draining soils, which a mushroom wouldn’t really like.

If you’re after an airy mix, a mushroom popping up in it might indicate that you need a few more chunks in it.

Are mushrooms a sign of good soil (or good luck)?

A Leucocoprinus birnbaumii popping up in your potted plant isn’t a good or a bad thing. It’s… just something that happened.

All we can say objectively is that a houseplant with a mushroom growing in it provides the correct environment for a mushroom. That tells us:

• There are nutrients in your soil. The mushroom won’t be produced unless there’s a tonne of nutrients
• The soil is damp. If your plant is too dry, you’re highly unlikely to get a mushroom
• The humidity spiked. If mushrooms pop up after a night of heavy rain, it’s because the humidity spiked and the mycelium was like ‘guys, it’s time’
• Your soil has life. Mushrooms are unlikely to grow if you use a lot of pesticides, fungicides or hydrogen peroxide

If your plant lives in a similar niche to Leucocoprinus birnbaumii in the wild, then it could be a good thing. If it doesn’t, it might be a bad thing… but it might not.

The perfect amount of worm castings in your soil could prompt a mushroom to grow and your soil would be healthy. But if you repot your snake plant in 50% compost and 50% houseplant soil from the garden centre, a mushroom could pop up, and that’s not a great soil mix for that plant.

In short, don’t automatically assume a mushroom = healthy soil OR a mushroom = unhealthy soil.

The fact that there’s never been a major attempt at getting rid of these mushrooms for good definitely points to them being either neutral or beneficial to houseplants.

Are mushrooms in houseplants lucky?

Mushrooms are considered lucky in a number of cultures, most likely due to their almost magical ability to appear and disappear overnight. However, I can’t find any evidence that houseplant mushrooms specifically are considered lucky by… anyone. Please let me know if you have information on this.

The Japanese believe shiitake are lucky, and Native Americans believe puffballs are lucky and use them in medicine. A LOT of cultures find psychoactive mushrooms lucky. I couldn’t find anything about Leucocoprinus birnbaumii though.

Though spreading from the tropics to potentially every plant pot in the world seems pretty lucky.

Apparently in the UK it’s unlucky to collect mushrooms on Sundays. As someone who’s lived her whole life in the UK, and who spent a lot of time foraging as a child, it doesn’t come up often.

How to get rid of mushrooms in houseplants

I leave them. They don’t do a significant amount of harm and I don’t have any kids. My only pets are fish (there’s never really been an issue with them), and two house rabbits that have to be kept separated from my plants for other reasons. They’ll pop up, release their spores, and disappear again in a day or two, so there’s not much point removing them.

But if you have pets or small children that might fancy a bite of mushroom, then it makes sense to remove them.

The easiest way to remove mushrooms from houseplants is to just pluck them out with your fingers and put them in the bin. Just be sure to wash your hands afterwards, because if you accidentally eat some they could make you ill.

How to stop mushrooms coming back

If the idea of mushrooms in your houseplants freaks you out, there are steps you can take that will reduce the chances of mushrooms setting up shop.

The good news is that mushrooms like specific conditions, and if you don’t provide those conditions, they likely won’t turn up. Since life finds a way, there are no guarantees, but we can try our best. (I can’t promise anything will work. They’re extremely ambitious fungi.)

Keep the top of the soil dry. If you keep the top of the soil dry, you’re making a less inviting home for the mycelium, and whilst it probably won’t be harmed, the chances of it producing a mushroom are lower. The bonus here is that it’s also an inhospitable environment for fungus gnats. You can:

• Bottom water your plants, and take them out of the water before the top of the soil is damp
• Top dress the soil with something that doesn’t retain water, like sand or gravel
• Put the plant in a sunny window so the top of the soil dries quickly (obvs only with plants that will appreciate a sunny window, and won’t just burn to a crisp)

Use a substrate that doesn’t hold much water. Don’t do this if it’s going to cause drought stress, but cacti, succulents and snake plants could really benefit from a more free-draining mix. Add grit or sand. Don’t do this for plants like Calathea and ferns, you’ll likely just end up underwatering them.

Make sure the pot drains well. If the soil stays wet, you increase the chance of mushrooms and of root rot, because the longer the soil stays wet, the less oxygen there is in it. The easiest fix is drainage holes. One is fine for terracotta, but a non-porous pot is better with a few. Don’t use gravel for drainage, all it does is reduce the amount of soil in the pot and create a perched water table.

Remove dead leaves and decaying matter. Decaying matter is the perfect food for the mycelium, so remove debris as soon as it drops. Not only will you reduce the chance of getting mushrooms, but you’ll also reduce the chances of getting fungus gnats, which are not fun.

Move the pot away from other plants. Not really suitable for people like me with hundreds of houseplants, but if you just have a few, keep them spread apart so that when mushrooms do pop up, their spores won’t travel into other plants. Leucocoprinus birnbaumii didn’t make it from the tropics to England just to be thwarted from spreading in one house.

Mycelium don’t do well in hot temperatures, so you can try heat pads, BUT Leucocoprinus birnbaumii seem to be pretty good at adapting to different temperatures, so I can’t promise that’ll work.

What not to bother with

Repotting. Not because it’ll damage your plant, but because it’s largely pointless. Unless you scrub the roots of the plant, you’ll just move the mycelium from one pot to another. A commonly recommended piece of advice is to remove the top layer of soil, but the mycelium are likely deeper than that. And a LOT of store-bought soil already contains spores before you open it.

Sterilising the soil. I don’t recommend it, because it gets rid of good microbes and bugs as well as bad ones. It will kill the mycelium, but unless you change the conditions you keep the plant in, more spores will germinate and more mushrooms will grow. Also, the second you fertilise your plants, you’re back to square one.

Fungicides, pesticides and hydrogen peroxide. They could get rid of the mycelium, but they won’t stop it coming back, and there are reports that Leucocoprinus birnbaumii aren’t particularly fazed by fungicides anyway. You can also compromise the quality of your substrate, and many organisms build up resistance over time. You don’t want to create a race of superthrips just to get rid of the odd mushroom.

Cinnamon. There is no evidence that cinnamon does ANYTHING to help houseplants. There’s evidence it has antifungal properties, but those studies were done in sterile lab conditions and haven’t been replicated in the real world. I once tried cinnamon as a top dressing (just to see if it’d get rid of gnats) and it just grew a layer of mould. The opposite of antifungal, it would seem.

Is it the same as mushrooms growing in my house, or mould?

No. Leucocoprinus birnbaumii feed on the nutrients in the soil, and the spores are highly unlikely to germinate if it’s too cold and there’s no nutrient-rich soil around.

The mushrooms that appear in damp bathrooms are Peziza domiciliana. Don’t eat those either!

Mushrooms and mould are both fungi, but they’re not the same, and mushrooms aren’t necessarily a sign of mould. Houseplant mould isn’t usually harmful to the plant, but can be a sign that the top of the soil isn’t drying out fast enough. It’s super common in early spring when the plant starts growing but it’s still not properly warm, and doesn’t usually indicate an issue.

There’s also that stuff that looks like little white balls, which commonly grows on soil and is a mostly harmless saprophytic fungus that won’t harm you or your plant, but might nick nutrients from the soil.

Can mushrooms help houseplants?

Some fungi can. Mycorrhizal fungi attach their mycelium to plant roots and help the plant absorb water and nutrients, and in return they take carbohydrates from the plant. It’s a symbiotic relationship that benefits everyone.

Leucocoprinus birnbaumii is not, from what I can glean, a mycorrhizal fungus. It’s saprotrophic, which means it’s just eating all the decaying matter in your soil rather than forming a relationship with your plant’s roots.

You can buy mycorrhizal fungi to add to houseplant soil, but personally, I don’t think the products are quite there yet. I go into why in my article on mycorrhizal fungi and houseplants.

Final thoughts

Mushrooms are common in houseplant soil because the particular species we get hails from the tropics and hitchhiked across the globe in botanists’ collections. They thrive in greenhouses and therefore make their way into millions of houseplants. If you then provide the right conditions, they’ll grow a mushroom.

Most of the mushrooms in houseplants are totally benign. They’re not a sign that something is wrong or right with the soil… they’re just there. Pluck them out if you have pets or kids, check the roots if it’s a plant that should be drying out, and otherwise, let them be.

Let me know if you’ve had mushrooms in your houseplants. I like to hear everyone’s experiences